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kotlinlang

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really strange issue with datatest and the intellij plugin. If I use `Int` as the type here, the tests render in the run panel correctly. But if I switch to `Number`, the tests render indexed, without parameters displayed, also it shows the FQDN rather than just the `Adder` name.

oh, and it also throws warnings due to the same test name
```WARN: Duplicated test name com.sunrun.pricing.flex.BaseAdder. To disable this message, set DuplicateTestNameMode to None.```

Seems to be due to `Number` not being considered a primitive when checking if it’s stable to use for generating names. ~Maybe it should be - any implementation of `Number`  must be a platform primitive, right?~ :thinking_face: nvm, anything can implement it so I suppose it makes sense

<https://github.com/kotest/kotest/blob/master/kotest-framework/kotest-framework-api/src/commonMain/kotlin/io/kotest/core/test/Identifiers.kt>

<https://github.com/kotest/kotest/blob/master/kotest-common/src/commonMain/kotlin/io/kotest/mpp/stable.kt>

You could perhaps provide the `nameFn` explicitly, like
```withData {
  nameFn = BaseAdder::toString,
  BaseAdder(..),
  ..```


<@UVAR0DXP0> that worked! interesting. not sure I understand why that worked though.

I think this page explains it better than I could :slightly_smiling_face:

<https://kotest.io/docs/framework/datatesting/custom-test-names.html>

&gt; Kotest will only use the toString() of the input class if it thinks the input class has a stable toString() value otherwise it will use the class name.
ah. that does explain it.